NZ793753A - Clutch having limited articulation - Google Patents

Abstract

clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the first part having a loop terminating in a pair of male connections, each of the male connections being pivotally coupled to a female connection of the second part. or, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the first part having a loop terminating in a pair of male connections, each of the male connections being pivotally coupled to a female connection of the second part.

Description

A clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector n a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a g apparatus, wherein the r includes a first part and a second part pivotal relative to the first part, the first part having a loop terminating in a pair of male connections, each of the male connections being pivotally coupled to a female connection of the second part.

NZ 793753 CLUTCH HAVING LIMITED ARTICULATION This is a divisional of New Zealand Patent Application No. 790116, the entire contents of which are incorporated herein by nce.

FIELD OF THE INVENTION This invention relates to a clutch. More particularly, but not exclusively, the invention s to an articulated clutch for lifting a concrete component by way of an anchor cast into the concrete component.

BACKGROUND OF THE INVENTION It is known to e a clutch for lifting concrete components where the clutch is used to lift, for example, concrete panels after casting by way of a cast-in ift anchor and for moving them to curing racks and later onto trucks for transportation to a construction site. However, the applicant has identified that there are disadvantages with existing lifting clutches.

The applicant has determined that it would be cial for there to be provided a clutch which overcomes or at least alleviates one or more disadvantages of ng clutches.

Accordingly, examples of the present invention seek to avoid or at least ameliorate the disadvantages of existing clutches.

SUMMARY OF THE INVENTION In accordance with one aspect of the t invention, there is provided a clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the al connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the first part having a loop terminating in a pair of male connections, each of the male tions being pivotally coupled to a female connection of the second part.

Preferably, the first part es a unitary ure forming an endless loop. More preferably, the second part has a first female connection and a second female connection, the first and second female connections being separated by a spacer integrally formed as part of said unitary structure. Even more preferably, the first female connection is at one side of the second part and the second female connection is at an opposite side of the second part.

Preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part. More preferably, the r is arranged to limit pivotal movement of the second part ve to the first part in at least one direction. Even more preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part in two directions.

In one form, the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents a tip of the locking ring handle passing through an inner loop of the second part.

Preferably, the first part includes a er arranged to bear against the second part at said limit.

Alternatively, the second part includes a shoulder arranged to bear against the first part at said limit.

In a preferred form, the coupler is ed to limit l movement of the second part relative to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle. More preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle from the engaged condition to the aged condition.

Preferably, the first part is connected to the second part by a pivotal coupling. More preferably, the pivotal coupling includes a first hinge at one side of the coupler and a second hinge at an opposite side of the coupler.

In a preferred form, the first hinge and the second hinge are arranged to provide pivotal movement along a common axis.

Preferably, the coupler includes a spacer n the first hinge and the second hinge.

More preferably, the spacer includes a stop for ng against the first part to limit rotation of the second part relative to the first part. Even more preferably, the spacer forms part of a unitary construction of the second part and the stop is adapted to abut against the first part to limit rotation of the second part relative to the first part.

In one form, the first part is provided with a tab for nt with the stop.

Preferably, the stop is in the form of a cutout having two stop surfaces, comprising a first stop surface for abutting one side of the tab and a second stop e for abutting an opposite side of the tab for limiting rotation of the second part relative to the first part in two directions.

In accordance with another aspect of the present invention, there is provided a clutch for lifting a concrete ent, including a toroidal connector, a latch in the form of a locking ring e relative to the toroidal tor between a aged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the first part being coupled to the second part pair of spaced hinges, the hinges being separated by a spacer formed as an integral part of the second part.

Preferably, the second part is formed by casting to have a unitary construction and wherein the spacer is formed as an al part of the second part by being cast as part of the unitary construction.

There is also disclosed a clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the al tor, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the coupler being ed to limit pivotal movement of the second part relative to the first part.

Preferably, the coupler is ed to limit pivotal movement of the second part relative to the first part in one direction. More preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents a tip of the locking ring handle passing through an inner loop of the second part.

In a preferred form, the first part includes a shoulder arranged to bear against the second part at said limit.

The second part may e a shoulder arranged to bear against the first part at said limit.

Preferably, the coupler is ed to limit pivotal movement of the second part relative to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle. More ably, the coupler is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle from the engaged condition to the disengaged condition.

There is also disclosed a clutch for lifting a concrete component, including a toroidal connector, a latch movable relative to the toroidal connector between a aged condition and an engaged condition, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part about a pin, and wherein the coupler includes a tamper evident indicator to indicate that the clutch has not been disassembled.

Preferably, the tamper evident indicator is arranged to indicate that the pin has not been d from the coupler.

In a red form, the coupler is provided with a bush around a l n of the pin. More preferably, the pin has a circular groove about its ference and the tamper evident indicator includes a member in engagement with the circular groove to prevent movement of the pin along its longitudinal axis relative to the bush.

More preferably, the member is anchored to the bush.

In one form, the member is in the form of a rivet.

Alternatively, the member is in the form of a roll pin.

There is also disclosed a clutch for lifting a concrete component, including a toroidal connector, a latch e relative to the toroidal tor between a disengaged condition and an engaged condition, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the toroidal connector has a circular seat for g upon a circular upper surface of a head of and anchor coupled to the al connector, wherein the circular seat ates in a radial bearing surface for abutment with a castellation of the .

Preferably, the circular seat has a first radial bearing surface for abutment with a first castellation of the anchor and a second, opposite, radial bearing surface for abutment with a second castellation of the anchor.

In a preferred form, the circular seat is circular about an arc having a centre at a central longitudinal axis of the latch. More preferably, the radial bearing surface is radial relative to a circle having a centre at the central longitudinal axis of the latch.

There is also disclosed a clutch for lifting a concrete component, including a toroidal connector, a latch e relative to the toroidal connector between a disengaged condition and an engaged condition, and a coupler for coupling the al tor to a lifting apparatus, wherein the coupler is articulated.

Preferably, the coupler includes a first part and a second part l relative to the first part, the first part forming a first loop engaged through the toroidal connector and the second part forming a second loop for receiving the lifting apparatus.

Preferably, the first loop is a different size to the second loop. More preferably, the first loop is smaller than the second loop.

In a red form, the second loop is adapted to allow direct fitment of a lifting chain while also allowing direct fitment of a lifting hook.

It is preferred that the coupler includes an elongated pin about a longitudinal axis of which the second part is pivotal relative to the first part.

Preferably, the latch is in the form of a circular latch passing through an inner ar passage of the toroidal connector.

There is also disclosed a clutch for lifting a concrete component, including a al connector, a latch movable relative to the toroidal connector between a disengaged condition and an engaged condition, and a coupler for coupling the toroidal connector to a lifting tus, wherein the coupler includes a first part and a second part pivotal relative to the first part about a pin, the first part having a first circular arc and the second part having a second circular arc, and wherein the pin is located such that a longitudinal axis of the pin is perpendicular to a line connecting a centre of the first arc to a centre of the second arc.

There is also sed a clutch for lifting a te component, including a toroidal connector, a latch in the form of a locking ring movable relative to the toroidal connector between a disengaged condition and an engaged condition, the locking ring having a handle ing ly outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the locking ring handle is ed to abut the coupler to limit rotational movement of the coupler relative to the toroidal connector. ably, the locking ring handle is ed to limit rotational movement of the coupler relative to the toroidal connector such that said limit prevents a tip of the locking ring handle passing through an inner loop of the coupler.

Preferably, the coupler is arranged to limit pivotal movement of the second part relative to the first part in two directions.

Preferably, the first part is connected to the second part by a pivotal coupling. More preferably, the pivotal ng includes a first hinge at one side of the coupler and a second hinge at an opposite side of the coupler. Even more preferably, the first hinge and the second hinge are arranged to provide pivotal movement along a common axis.

In a preferred form, the coupler includes a bush between the first hinge and the second hinge. More preferably, the bush includes a stop for abutting against the first part or the second part to limit rotation of the second part relative to the first part. Even more preferably, the bush is arranged to rotate with the second part and the stop is adapted to abut against the first part to limit rotation of the second part relative to the first part.

Preferably, the first part is provided with a tab for abutment with the stop. More preferably, the stop is in the form of a cutout having two stop es, comprising a first stop surface for abutting one side of the tab and a second stop surface for abutting an opposite side of the tab for limiting on of the second part relative to the first part in two directions.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is further bed by way of non-limiting example only with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of an articulated clutch for lifting a concrete component in accordance with an example of the present invention; Figure 2 shows a side view of the articulated clutch; Figure 3 shows a front view of the articulated clutch; Figure 4 shows an exploded view of the articulated clutch; Figure 5 shows a front view of the articulated clutch, depicting a tamper t device incorporated into the ; Figure 6 shows a side cross-sectional view of the articulated clutch, depicting on of the tamper evident device when in situ; Figure 7 is a detailed perspective view of an end of the tamper evident device when in situ; Figure 8 shows a perspective view of the articulated , depicting a limit of rotation of a second part of a coupler relative to a first part of the coupler; Figure 9a shows a front view of the articulated clutch, depicting the limit of rotation of the second part relative to the first part; Figure 9b shows a cross-sectional view of the articulated clutch taken along line A-A shown in Figure 9a; Figure 9c shows a side view of the articulated clutch, depicting the limit of rotation of the second part relative to the first part; Figure 10 shows a side perspective view of a toroidal connector of the articulated ; Figure 11a shows a front view of the toroidal connector; Figure 11b shows a side sectional view of the toroidal connector taken along line A-A shown in Figure 11a; Figure 12 shows an opposite side perspective view of the toroidal connector; Figure 13 shows a cross-sectional view of the toroidal connector when connected to a head of a cast-in anchor, taken through a central plane of the toroidal connector; Figure 14 shows a front view of a r of the articulated clutch, depicting an axis of rotation of the second part relative to the first part with respect to a central line of the coupler ting a centre of a circular arc of the first part with a centre of a circular arc of the second part; Figure 15 shows a side view of an articulated clutch in accordance with another e, depicting the limit of rotation of the coupler relative to the toroidal connector; Figure 16 shows a perspective view an articulated clutch in accordance with another example, depicting a locking ring handle being sufficiently long to limit rotation of the r relative to the al connector; Figure 17 shows a top view of the articulated clutch shown in Figure 16; Figure 18 shows a side view of the articulated clutch shown in Figure 16; Figure 19 shows a perspective view of the articulated clutch in accordance with another e; Figure 20 shows a detailed view of portion labelled "B" in Figure 19; Figure 21 shows a front view of the articulated clutch shown in Figure 19 and Figure 20; and Figure 22 shows a detailed view of section A-A shown in Figure 21.

Figure 23 shows a perspective view of an lated clutch in accordance with another example in which a lower loop has two male connections; Figure 24 shows an opposite perspective view of the articulated clutch of Figure Figure 25 shows a front view of the articulated clutch shown in Figure 23 and Figure 24; and Figure 26 shows a rear view of the articulated clutch shown in Figures 23 to 25.

DETAILED DESCRIPTION As can be seen in Figures 1 to 18 of the drawings, the present invention may provide an lated clutch for lifting a concrete component. ageously, the articulated clutch has a coupler including a first part and a second part pivotal relative to the first part. The first part forms a first loop and the second part forms a second loop. The two loops are dissimilar in size such that the top loop (when lifting) provided by the second loop will accept a crane or lifting hook but can still accept a suitable size chain fitted directly to the top loop.

More specifically, as shown in Figures 1 to 4, there is provided a clutch 10 for lifting a concrete component (not shown). The concrete component may take several forms including, but not limited to, a concrete panel. The concrete component may have a cast in edge lift anchor (for example), the anchor having an eye which is used for connection to a toroidal connector of the clutch 10 for g the concrete panel.

The clutch 10 includes a toroidal connector 12 and a latch 14. The latch 14 is e relative to the toroidal connector 12 between a disengaged condition (in which the latch 14 is retracted into a toroidal sleeve of the toroidal connector 12) and an engaged condition (see Figure 2) in which the latch 14 spans a gap of the toroidal connector 12 for engagement with an eye of and anchor cast into a concrete component. The clutch also includes a coupler 16 for coupling the toroidal connector 12 to a lifting apparatus 18, wherein the coupler 16 is articulated.

The r 16 includes a first part 20 and a second part 22 pivotal ve to the first part, the first part forming a first loop 24 d through the toroidal connector 12 and the second part 22 forming a second loop 26 for receiving the lifting apparatus 18.

As shown, the first loop 24 is a different size to the second loop 26. More specifically, the first loop 24 is r than the second loop 26. The second loop 26 is adapted to allow direct fitment of a lifting chain while also allowing direct fitment of a lifting hook.

Accordingly, the coupler 16 allows the direct fitment of a suitable size chain like a hammerlock but also allows for direct fitment to a lifting hook as shown in figure 5.

The articulation of this format of clutch handle (in the form of coupler 16) addresses the issue of welded handles getting bent around the head of a concrete panel as the panel is lifted off a truck at a building site, as the te panel is lifted and then rotated 90° before being positioned. It does this while also meeting the needs of the precast y where the clutch 10 is used to lift concrete panels from horizontal to vertical after casting and for moving them to curing racks and later onto trucks for transportation to a building site.

The t size of the two loops (the first loop 24 and the second loop 26) also allows for greater head height within the y, allowing for a gain in lifting height. This in turn allows for sed panel sizes as well as increased manoeuvrability within the factory, where lifting height is limited by the gantry height.

As shown in Figure 4, the coupler 16 includes an elongated axle pin 28 about a longitudinal axis of which the second part 22 is pivotal ve to the first part 20. The first part 20 includes a forked end and a rked end. The forked end of the first part 20 engages with a non-forked end of the second part 22, whereas the non-forked end of the first part 20 engages with a forked end of the second part 22. The ends of the first part 20 and the second part 22 are provided with apertures through which the axle pin 28 is passed so as to hold together in pivotal relationship the first part 20 and the second part 22.

With reference to Figure 4, the latch 14 is in the form of a circular latch passing h an inner circular passage of the toroidal connector 12. The latch 14 has a handle 30 for moving the latch 14 between the disengaged condition and the d condition, the handle 30 extending lly radially outwardly relative to a centre of the toroidal connector 12.

As shown most clearly in Figure 14, the first part 20 has a first circular arc 32 and the second part 22 has a second circular arc 34. The pin 28 is d such that a longitudinal axis of the pin 28 is perpendicular to a line 36 connecting a centre 38 of the first arc 32 to a centre 40 of the second arc 34.

Accordingly, the axle pin 28 runs perpendicular to the centre line between the arcs of the two loops 24, 26. This allows the handle (coupler 16) to be symmetrical such that when rotated about the toroidal connector 12, the coupler 16 has the same angular movement either way. This perpendicular configuration may also assist in the articulation of the coupler 16 when it needs to be bent around the end of a concrete panel being lifted.

Turning to Figures 8 to 9c, the latch 14 in the form of the locking ring may have a handle 30 extending generally radially outwardly from the toroidal connector 12. The coupler 16 may be specifically arranged to limit pivotal movement of the second part 22 relative to the first part 20. In other words, in Figure 2 the first part 20 and the second part 22 are shown in a co-planar configuration, whereas in Figures 8 to 9c there is shown a limit of l movement of the second part 22 relative to the first part 20.

In one form, the coupler 16 may be ed to limit l movement of the second part 22 ve to the first part 20 in one direction. The coupler 16 may also be arranged to limit pivotal movement of the second part 22 relative to the first part 20 such that the limit prevents a tip 42 of the locking ring handle passing through an inner loop 26 of the second part 22.

As best shown in the cross-sectional drawing shown in Figure 9B, the first part may include a shoulder 44 arranged to bear against the second part 22 at the limit.

Alternatively, or in addition, the second part 22 may include a shoulder arranged to bear against the first part 20 at the limit.

In a preferred example, the coupler 16 is arranged to limit pivotal movement of the second part 22 relative to the first part 20 such that the limit prevents the second part 22 from engaging with the locking ring handle 30 to rotate the locking ring handle 30.

More specifically, the coupler 16 may be arranged to limit pivotal movement of the second part 22 relative to the first part 20 such that the limit ts the second part 22 from engaging with the locking ring handle 30 to rotate the locking ring handle 30 from the engaged condition to the disengaged condition.

In this way, the two loops 24, 26 are limited in rotation in one direction to eliminate the large loop being able to hook under the locking ring handle 30. The applicant has identified that, where the upper loop (secondly 26) is large enough to accept a lifting hook, then that loop has the potential to cook under the g ring handle 30 and could allow the clutch 10 to become disconnected from the anchor ntionally.

Advantageously, by limiting rotation in this way examples of the present invention are able to prevent unintentional disconnection.

As shown in Figures 4 to 7, the second part 22 is pivotal relative to the first part 20 about the axle pin 28. The coupler 16 may also include a tamper evident tor 46 to indicate that the clutch 10 has not been disassembled. The tamper evident indicator may be is ed to indicate that the axle pin 28 has not been removed from the r 16. In the example shown, the coupler 16 is provided with a bush 48 around a central portion of the axle pin 28, the central portion being between the distal end of the first part 20 and the second part 22. The second part 22 may be provided with longitudinal slots which are received in corresponding longitudinal grooves of the bush 48 to keep the bush 48 aligned relative to the second part 22 and to prevent rotation of the bush 48 ve to the second part 22.

With nce to Figure 4, the pin 28 may have a circular groove 50 about its circumference and the tamper evident indicator 46 may include a member in engagement with the circular groove 50 to prevent movement of the pin 28 along its longitudinal axis relative to the bush 48. In addition, the toroidal connector 12 may be provided with a stop pin 52 to limit on of the latch 14 relative to the toroidal connector 12. The member 46 may be anchored to the bush 48. With reference to Figure 6, the member 46 may be in the form of a rivet which passes through the bush 48 and has a flange at each end to retain the rivet relative to the bush 48. Alternatively, the member may be in the form of a roll pin.

In this way, there is provided a tamper evident centre bush 48. The bush 48 may be ed to match the loops 24, 26, the bush 48 being secured by either a rivet or a roll pin that does not pass through the middle of the axle pin 28 but passes tangentially through the groove 50 on the axle pin 28. If secured by a rivet, the rivet will be deformed to secure it and the deformed end may have a branded logo (see Figure 5 and Figure 7) to te the handle (coupler 16) has not been tampered with. If a roll pin is used, then a seal bly in the form of epoxy or solder) may be used to indicate the clutch has not been disassembled.

As will be appreciated from the drawings, the bush 48 has a non-cylindrical shape. The locking pin or rivet 46 runs tangentially through the groove 50 in the axle pin 28.

Accordingly, this provides an indication to the user that the clutch 10 has not been tampered with since proof testing. The applicant has identified that a commercial hammerlock can be disassembled and reassembled without it being evident that this has ed. Therefore, the original proof testing and certification could be invalid as this must be conducted anytime the clutch is ed.

Advantageously, the incorporation of a tamper evident feature gives the user confidence that the clutch 10 has not been tampered with since proof testing. The unique shape of the bush 48 allows the rivet or cross pin 46 to hold the axle 28 by the groove 50 rather than passing the centre of the axle 28. This creates far less stress concentration, making the axle 28 stronger. The unique shape of the bush 48 also allows the use of the tamper evident rivet 46. The tangentially positioned groove 50 allows for easier assembly of the system compared to that of a centrally located hole as less alignment is required (that is, alignment is only ed in the x-axis and not in both x and y axes).

Turning now to Figures 10 to 13, the toroidal connector 12 may be provided with a ar seat 54 for sitting upon a circular upper surface 56 of a head 58 of an anchor 60 coupled to the toroidal connector 12. The circular seat 54 terminates in a radial bearing e 62 for face-to-face abutment with a castellation 64 of the anchor 60.

As can be seen most clearly in Figure 13, the circular seat 54 has a first radial bearing e 62 for abutment with a first castellation 64 of the anchor and a , opposite, radial bearing surface 62 for abutment with a second castellation 64 of the anchor 60.

In the example shown, the circular seat 54 is circular about an arc 66 having a centre at a central longitudinal (tangential) axis 68 of the latch 14. More ically, the radial bearing surface 62 is radial relative to a circle having a centre at the central longitudinal axis 68 of the latch 14.

Advantageously, the provision of the radial bearing surfaces 62 improve the interface of the toroidal connector 12 and the anchor 60, when ed with ng connectors which abut at an edge or point. The applicant has identified that the face-to-face bearing provides less pressure owing to the greater surface area of contact, ng wear on the toroidal connector 12. In particular, the applicant has identified that previous clutch designs for lated anchors would see the sides of the torus bear on the castellations (or in a point or line contact where the sides of the torus meet the curved cut out). In the example of the invention shown, a new angled face interacts with the angled face of the anchor 60 to achieve a far greater bearing area resulting in less wear on the torus over time. This is achieved by way of the angled faces on the toroidal connector 12 which bear against the lations 64 on the head 58 of the anchor 60. This is in contrast to existing arrangements where a toroidal connector bears on flat faces of the anchor or, where the anchor is castellated, the sides of the torus bear on the castellations.

With reference to Figures 15 to 18, there is shown an alternative example of the present invention in which the locking ring handle 30 is arranged to abut the coupler 16 to limit rotational movement of the coupler 16 relative to the toroidal connector 12. In particular, the locking ring handle 30 is arranged to limit rotational movement of the coupler 16 relative to the toroidal connector 12 such that the limit prevents a tip 42 of the locking ring handle 30 passing through an inner loop 26 of the coupler 16. This may be achieved by dimensioning the locking ring handle 30 such that the tip 42 of the locking ring handle 30 extends radially r from a centre of the toroidal connector 12 than an outermost edge of the coupler 16.

Turning to Figures 19 to 22, there is shown an example of the present invention in which the r 16 is arranged to limit pivotal movement of the second part 22 relative to the first part 20 in two directions. More specifically, as can be seen in Figure 19, the first part 20 is ted to the second part 22 by a pivotal coupling 70. In the example shown, the pivotal coupling 70 includes a first hinge 72 at one side of the coupler 16 and a second hinge 74 at an opposite side of the r 16. As can be seen, the first hinge 72 and the second hinge 74 are arranged to provide pivotal nt of the second part 22 relative to the first part 21 along a common axis which may be ensured by a single axle pin 28.

In the example shown in Figures 19 to 22, the pivotal coupling 70 includes a bush 48 between the first hinge 72 and the second hinge 74. The bush 48 includes a stop 76 for abutting against the first part 20 or the second part 22 to limit rotation of the second part 22 relative to the first part 20. The bush 48 may be arranged to rotate with the second part 22 (for example, engaged with the second part 22 by way of a tongue and groove connection) and the stop 76 may be adapted to abut against the first part 20 to limit rotation of the second part 22 relative to the first part 20.

Figure 20 shows an enlarged and detailed view of the portion labelled "B" in Figure 19.

In Figure 20 it can be seen that the first part 20 is provided with a tab 78 for abutment with the stop 76.

Figure 21 shows a front view of the coupler 16, and Figure 22 shows an enlarged and detailed view of the cross-section labelled A-A in Figure 21. With reference to Figure 22, the stop 76 may be in the form of a cutout 80 having two stop es, comprising a first stop surface 82 for abutting one side of the tab 78 and a second stop surface 84 for ng an opposite side of the tab for limiting on of the second part 22 relative to the first part 20 in two directions.

Advantageously, this ement enables the limiting of angular movement of the second part 22 relative to the first part 20 in two directions and avoids a weakness which may otherwise be incurred if the limiting mechanism is attempted to be ed within the first hinge 72 and/or the second hinge 74. The arrangement shown in figures 19 to 22 takes advantage of there being no load or only little load on the coupler 16 when the rotation limiting mechanism is required to perform its duty. In other words, the arrangement shown in Figures 19 to 22 s how rotation of the upper loop relative to the lower loop is achieved. In this revised version, this limitation of rotation is achieved between radial shoulders in the centre bush 48 that limit the movement of a lug or tab on the inside of the lower loop.

The revised arrangement limits rotation in both directions, not just one direction. It will be understood by those skilled in the art that the two directions may be different (for example, in magnitude of limitation), thereby preventing the large loop – the second part – from interacting with the locking ring handle while allowing extra rotation in the opposite direction. This revised arrangement works between the lower loop – the first part 20 – and the centre bush 48, where the centre bush 48 is keyed to the upper bush to maintain alignment with the upper loop.

With reference to Figures 23 to 26, there is shown an example of the present invention in which the coupler 16 is arranged to limit pivotal movement of the second part 22 relative to the first part 20 in two directions, but with the first part 20 terminating in a male connection 86 at each end and the second part 22 terminating in a female connection 88 at each end. More specifically, as can be seen in Figure 23, the first part is connected to the second part 22 by a pivotal ng 70. In the example shown, the pivotal coupling 70 includes a first hinge 72 at one side of the coupler 16 and a second hinge 74 at an opposite side of the coupler 16. As can be seen, the first hinge 72 and the second hinge 74 are arranged to e l movement of the second part 22 relative to the first part 21 along a common axis which may be ensured by a single axle pin 28.

In particular, the first hinge 72 is formed by a female connection 88 forming a slot into which the male connection 86 of the first part 20 is ed. Similarly, the second hinge 74 is formed by a female tion 88 at an opposite side of the second part 22, also forming a slot into which the male tion 86 at the opposite end of the first part 20 is inserted. Accordingly, it will be iated that the first part 20 terminates in two ends, each of the end forming a male connection 86 four fitting in a corresponding female connection 88 of the second part 22. The female connections 88 are separated by a central spacer 90 and may be at opposite sides of the second part 22 did in the example shown in Figures 23 to 26. The spacer 90 is formed as an integral part of the second part 22, in contrast to the bush 48 of the example shown in Figure 19.

Advantageously, the applicant has determined that having the first part 20 terminating in male connections 86 may be superior in performance when compared to the female/male terminals of the first part 20 shown in Figure 19. In particular, the applicant has determined that the symmetry of the male als accommodates the toroidal connector 12 while avoiding unwanted stress concentrations which may lead to fatigue on the heavier side of the first part 20. Accordingly, the ement shown in Figures 23 to 26 may be better balanced as well as being stronger, tougher and more robust. As the spacer 90 is formed as an integral part of the second part 22, the second part 22 forms an endless loop having a unitary structure which also serves to improve strength. The symmetry of the first part 20 facilitates equal loading of the coupler 16 and also avoids twisting.

Therefore, it will be understood by those skilled in the art that the articulated clutch 10 shown in Figures 23 to 26 has a completely symmetrical left/right design, with a rigid upper loop (formed by second part 22) which has two female connections 88 where the lower loop (formed by first part 20) has two male connections 86. This means that the upper loop is no longer able to accept a chain being ly fitted to it, in contrast to the version having the removable bush 48 shown in Figures 1 to 22.

In the e shown in Figures 23 to 26, the pivotal coupling 70 includes the spacer 90 between the first hinge 72 and the second hinge 74. The spacer 90 es a stop 76 for abutting against the first part 20 to limit rotation of the second part 22 ve to the first part 20. Being ally formed as part of the second part 22, the spacer 90 rotates with the second part 22 and the stop 76 may be adapted to abut against the first part 20 to limit rotation of the second part 22 relative to the first part 20.

In Figure 25 it can be seen that the first part 20 is provided with a tab 78 for abutment with the stop 76. With reference to Figure 25 and Figure 26, the stop 76 may be in the form of a cutout 80 having two stop surfaces, sing a first stop surface 82 for abutting one side of the tab 78 and a second stop surface 84 for ng an opposite side of the tab for limiting rotation of the second part 22 relative to the first part 20 in two directions.

This arrangement enables the limiting of angular movement of the second part 22 relative to the first part 20 in two directions and avoids a weakness which may otherwise be incurred if the ng mechanism is ted to be ed within the first hinge 72 and/or the second hinge 74. The arrangement shown in Figures 23 to 26 takes advantage of there being no load or only little load on the coupler 16 when the rotation limiting ism is required to perform its duty. In other words, the arrangement shown in Figures 23 to 26 changes how rotation of the upper loop relative to the lower loop is achieved. In this revised version, this limitation of rotation is ed between radial shoulders in the central spacer 90 that limit the movement of a lug or tab on the inside of the lower loop.

The revised arrangement limits rotation in both directions, not just one ion. It will be understood by those skilled in the art that the two directions may be different (for example, in ude of limitation), thereby preventing the large loop – the second part – from interacting with the locking ring handle while allowing extra rotation in the opposite direction. This revised arrangement works between the lower loop – the first part 20 – and the l spacer 90, where the central spacer 90 is formed as part of the unitary structure of the upper loop While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the ion. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common l knowledge in the field of endeavour to which this specification relates.

List of features: Clutch 12 Toroidal connector 14 Latch 16 Coupler 18 Lifting apparatus First part 22 Second part 24 First loop 26 Second loop 28 Axle pin Handle of the latch 32 First circular arc 34 Second circular arc 36 Line 38 Centre of the first arc 40 Centre of the second arc 42 Tip of the locking ring handle 44 Shoulder 46 Tamper t indicator 48 Bush 50 Circular groove 52 Stop pin 54 Circular seat 56 Circular upper surface 58 Head 60 Anchor 62 Radial bearing e 64 Castellation 66 Arc 68 Central longitudinal axis of the latch 70 Pivotal coupling 72 First hinge 74 Second hinge 76 Stop 78 Tab 80 Cutout 82 First stop surface 84 Second stop surface 40 86 Male connection 88 Female connection 90 Spacer

Claims (22)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the al connector between a disengaged condition and an engaged condition, the locking ring having a handle extending radially outwardly from the toroidal connector, and a coupler for coupling the toroidal connector to a lifting tus, wherein the r includes a first part and a second part pivotal relative to the first part, the first part having a loop terminating in a pair of male connections, each of the male tions being pivotally coupled to a female connection of the second part.

2. A clutch as claimed in claim 1, n the first part includes a unitary structure forming an endless loop.

3. A clutch as claimed in claim 2, wherein the second part has a first female connection and a second female connection, the first and second female connections being separated by a spacer integrally formed as part of said unitary structure.

4. A clutch as claimed in claim 3, wherein the first female connection is at one side of the second part and the second female connection is at an opposite side of the second part.

5. A clutch as claimed in any one of claims 1 to 4, wherein the coupler is ed to limit pivotal movement of the second part relative to the first part.

6. A clutch as claimed in claim 5, wherein the coupler is arranged to limit pivotal movement of the second part relative to the first part in at least one direction.

7. A clutch as claimed in claim 6, wherein the coupler is arranged to limit pivotal nt of the second part relative to the first part in two ions.

8. A clutch as claimed in claim 6 or claim 7, wherein the r is arranged to limit pivotal movement of the second part relative to the first part such that said limit prevents a tip of the locking ring handle passing through an inner loop of the second part.

9. A clutch as claimed in any one of claims 1 to 8, wherein the first part es a shoulder arranged to bear against the second part at said limit.

10. A clutch as claimed in any one of claims 1 to 8, wherein the second part includes a shoulder arranged to bear against the first part at said limit.

11. A clutch as claimed in any one of claims 1 to 10, wherein the coupler is ed to limit pivotal movement of the second part relative to the first part such that said limit ts the second part from engaging with the locking ring handle to rotate the locking ring handle.

12. A clutch as claimed in claim 11, wherein the coupler is arranged to limit l movement of the second part relative to the first part such that said limit prevents the second part from engaging with the locking ring handle to rotate the locking ring handle from the engaged condition to the disengaged ion.

13. A clutch as claimed in any one of claims 1 to 12, wherein the first part is connected to the second part by a pivotal coupling.

14. A clutch as claimed in claim 13, wherein the pivotal coupling includes a first hinge at one side of the coupler and a second hinge at an opposite side of the coupler.

15. A clutch as claimed in claim 14, wherein the first hinge and the second hinge are ed to provide pivotal movement along a common axis.

16. A clutch as claimed in claim 14 or claim 15, wherein the coupler includes a spacer between the first hinge and the second hinge.

17. A clutch as claimed in claim 16, wherein the spacer includes a stop for abutting against the first part to limit rotation of the second part relative to the first part.

18. A clutch as claimed in claim 17, wherein the spacer forms part of a unitary construction of the second part and the stop is adapted to abut t the first part to limit rotation of the second part relative to the first part.

19. A clutch as claimed in claim 18, wherein the first part is provided with a tab for abutment with the stop.

20. A clutch as claimed in claim 19, wherein the stop is in the form of a cutout having two stop es, comprising a first stop surface for abutting one side of the tab and a second stop surface for abutting an opposite side of the tab for limiting rotation of the second part relative to the first part in two directions.

21. A clutch for lifting a concrete component, including a toroidal connector, a latch in the form of a locking ring movable relative to the al connector between a disengaged condition and an d condition, the locking ring having a handle extending radially outwardly from the al connector, and a coupler for coupling the toroidal connector to a lifting apparatus, wherein the coupler includes a first part and a second part pivotal relative to the first part, the first part being d to the second part pair of spaced hinges, the hinges being separated by a spacer formed as an integral part of the second part.

22. A clutch as claimed in claim 21, wherein the second part is formed by casting to have a unitary construction and wherein the spacer is formed as an integral part of the second part by being cast as part of the unitary construction.